Battery power systems can include one or more strings of batteries electrically coupled in a parallel or series configuration to facilitate increasing the power that is available to the system in which the batteries are connected. The battery strings can be connected to a charger that charges the battery strings for use in a battery power system. Overcharging a battery can damage the battery and/or reduce the effective operational life of the battery. Undercharging a battery can reduce the time the battery can be utilized in the system.
Existing systems for connecting multiple battery strings to a charger can include the use of open loop controls to synchronously connect all battery strings to the charger with a constant voltage charge or constant current followed by a constant voltage charge. Recharging the battery with a constant voltage or a constant current followed by a constant voltage may control the charging of the battery strings to keep the overall battery system current within a given limit, without taking into account the current limit of each individual battery string within the battery system. Other systems can include a step incremental voltage control that increases the voltage of the charger to a certain limit after a specified time period or can include ramping the battery voltage within given current limits. However, this does not provide for closed loop control and can require a long response time to connect the multiple battery strings to the charger. Additionally, this type of control of battery charging can result in an override of an individual current limit for a battery string.
Thus, a need exists for improved systems and methods for connecting multiple battery strings to a charger. Systems and methods that can provide for closed loop control that is sensitive to a string current limit for each of the plurality of battery strings while shortening connection and recharge times would be particularly useful.